Documentation

# eyediagram

Generate eye diagram

## Syntax

```eyediagram(x,n) eyediagram(x,n,period) eyediagram(x,n,period,offset) eyediagram(x,n,period,offset,plotstring) eyediagram(x,n,period,offset,plotstring,h) h = eyediagram(...) ```

## Description

`eyediagram(x,n) ` creates an eye diagram for the signal `x`, plotting `n` samples in each trace. `n` must be an integer greater than 1. The labels on the horizontal axis of the diagram range between -1/2 and 1/2. The function assumes that the first value of the signal, and every `n`th value thereafter, occur at integer times. The interpretation of `x` and the number of plots depend on the shape and complexity of `x`:

• If `x` is a real two-column matrix, `eyediagram` interprets the first column as in-phase components and the second column as quadrature components. The two components appear in different subplots of a single figure window.

• If `x` is a complex vector, `eyediagram` interprets the real part as in-phase components and the imaginary part as quadrature components. The two components appear in different subplots of a single figure window.

• If x is a real vector, `eyediagram` interprets it as a real signal. The figure window contains a single plot.

`eyediagram(x,n,period)` is the same as the syntax above, except that the labels on the horizontal axis range between -`period/2` and `period/2`.

`eyediagram(x,n,period,offset)` is the same as the syntax above, except that the function assumes that the (`offset+1`)st value of the signal, and every `n`th value thereafter, occur at times that are integer multiples of `period`. The variable `offset` must be a nonnegative integer between 0 and `n-1`.

`eyediagram(x,n,period,offset,plotstring)` is the same as the syntax above, except that `plotstring` determines the plotting symbol, line type, and color for the plot. `plotstring` is a character vector whose format and meaning are the same as in the `plot` function. The default value is `'b-'`, which produces a blue solid line.

`eyediagram(x,n,period,offset,plotstring,h)` is the same as the syntax above, except that the eye diagram is in the figure whose handle is `h`, rather than in a new figure. `h` must be a handle to a figure that `eyediagram` previously generated.

### Note

You cannot use `hold on` to plot multiple signals in the same figure.

`h = eyediagram(...)` is the same as the earlier syntaxes, except that `h` is the handle to the figure that contains the eye diagram.

## Examples

For an online demonstration, type `showdemo scattereyedemo`.